code: def __len__(self):
      return len(self.list)
  
imports: from collections.abc import Sequence
  from typing import List, Union
  import numpy
  import torch
  from sahi.annotation import BoundingBox, Category, Mask
  from sahi.prediction import ObjectPrediction
label_desc: Use image node_id 4 for calling the ObjectPredictionList obj's underlying member method code with example usage: obj.__len__() and returns: len